Performance of 3D printed topologically optimized novel auxetic structures under compressive loading: experimental and FE analyses

The auxetic structures, because of their negative Poisson's ratio, have a lot of potential applications in the aerospace and automobile industry due to their exceptional mechanical properties under bending, shear, and compression loads. In this study, three novel auxetic structures were prepared by creating modifications in the existing ones found in the literature. The in-plane mechanical performance of the novel structures under uniaxial compression loads was evaluated using experimentally validated finite element analysis (FEA) models. Moreover, their deformation and collapse behavior was also examined. It was found that all of the new auxetic structures possess higher Young's modulus and energy absorption capacities as compared to the conventional re-entrant structure. To further enhance their aforementioned properties, a topology optimization technique, i.e., shape optimization, whose effect on the mechanical performance of auxetic structures is not yet explored, was applied to the conventional and the new structures. The mechanical properties of shape-optimized structures were found to be significantly better than the un-optimized structures. Hence, auxetic structures, with compressive properties superior to the traditional ones were developed in this research which are favorable for high load applications. The modifications made to conventional structures, as well as the shape optimization technique utilized in this research, can be used as a guideline to produce other high-performance auxetic structures.